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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ATA Security Feature Set | FILES | BUGS | AUTHOR | SEE ALSO | COLOPHON |
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HDPARM(8) System Manager's Manual HDPARM(8)
hdparm - get/set SATA/IDE device parameters
hdparm [options] [device ...]
hdparm provides a command line interface to various kernel interfaces
supported by the Linux SATA/PATA/SAS "libata" subsystem and the older
IDE driver subsystem. Many newer (2008 and later) USB drive
enclosures now also support "SAT" (SCSI-ATA Command Translation) and
therefore may also work with hdparm. E.g. recent WD "Passport"
models and recent NexStar-3 enclosures. Some options may work
correctly only with the latest kernels.
When no options are given, -acdgkmur is assumed. For "Get/set"
options, a query without the optional parameter (e.g. -d) will query
(get) the device state, and with a parameter (e.g., -d0) will set the
device state.
-a Get/set sector count for filesystem (software) read-ahead.
This is used to improve performance in sequential reads of
large files, by prefetching additional blocks in anticipation
of them being needed by the running task. Many IDE drives
also have a separate built-in read-ahead function, which
augments this filesystem (software) read-ahead function.
-A Get/set the IDE drive´s read-lookahead feature (usually ON by
default). Usage: -A0 (disable) or -A1 (enable).
-b Get/set bus state.
-B Get/set Advanced Power Management feature, if the drive
supports it. A low value means aggressive power management and
a high value means better performance. Possible settings
range from values 1 through 127 (which permit spin-down), and
values 128 through 254 (which do not permit spin-down). The
highest degree of power management is attained with a setting
of 1, and the highest I/O performance with a setting of 254.
A value of 255 tells hdparm to disable Advanced Power
Management altogether on the drive (not all drives support
disabling it, but most do).
-c Get/set (E)IDE 32-bit I/O support. A numeric parameter can be
used to enable/disable 32-bit I/O support. Currently
supported values include 0 to disable 32-bit I/O support, 1 to
enable 32-bit data transfers, and 3 to enable 32-bit data
transfers with a special sync sequence required by many
chipsets. The value 3 works with nearly all 32-bit IDE
chipsets, but incurs slightly more overhead. Note that
"32-bit" refers to data transfers across a PCI or VLB bus to
the interface card only; all (E)IDE drives still have only a
16-bit connection over the ribbon cable from the interface
card.
-C Check the current IDE power mode status, which will always be
one of unknown (drive does not support this command),
active/idle (normal operation), standby (low power mode, drive
has spun down), or sleeping (lowest power mode, drive is
completely shut down). The -S, -y, -Y, and -Z options can be
used to manipulate the IDE power modes.
-d Get/set the "using_dma" flag for this drive. This option now
works with most combinations of drives and PCI interfaces
which support DMA and which are known to the kernel IDE
driver. It is also a good idea to use the appropriate -X
option in combination with -d1 to ensure that the drive itself
is programmed for the correct DMA mode, although most BIOSs
should do this for you at boot time. Using DMA nearly always
gives the best performance, with fast I/O throughput and low
CPU usage. But there are at least a few configurations of
chipsets and drives for which DMA does not make much of a
difference, or may even slow things down (on really messed up
hardware!). Your mileage may vary.
--dco-freeze
DCO stands for Device Configuration Overlay, a way for vendors
to selectively disable certain features of a drive. The
--dco-freeze option will freeze/lock the current drive
configuration, thereby preventing software (or malware) from
changing any DCO settings until after the next power-on reset.
--dco-identify
Query and dump information regarding drive configuration
settings which can be disabled by the vendor or OEM installer.
These settings show capabilities of the drive which might be
disabled by the vendor for "enhanced compatibility". When
disabled, they are otherwise hidden and will not show in the
-I identify output. For example, system vendors sometimes
disable 48_bit addressing on large drives, for compatibility
(and loss of capacity) with a specific BIOS. In such cases,
--dco-identify will show that the drive is 48_bit capable, but
-I will not show it, and nor will the drive accept 48_bit
commands.
--dco-restore
Reset all drive settings, features, and accessible capacities
back to factory defaults and full capabilities. This command
will fail if DCO is frozen/locked, or if a -Np maximum size
restriction has also been set. This is EXTREMELY DANGEROUS
and will very likely cause massive loss of data. DO NOT USE
THIS COMMAND.
--direct
Use the kernel´s "O_DIRECT" flag when performing a -t timing
test. This bypasses the page cache, causing the reads to go
directly from the drive into hdparm's buffers, using so-called
"raw" I/O. In many cases, this can produce results that
appear much faster than the usual page cache method, giving a
better indication of raw device and driver performance.
--drq-hsm-error
VERY DANGEROUS, DON'T EVEN THINK ABOUT USING IT. This option
causes hdparm to issue an IDENTIFY command to the kernel, but
incorrectly marked as a "non-data" command. This results in
the drive being left with its DataReQust(DRQ) line "stuck"
high. This confuses the kernel drivers, and may crash the
system immediately with massive data loss. The option exists
to help in testing and fortifying the kernel against similar
real-world drive malfunctions. VERY DANGEROUS, DO NOT USE!!
-D Enable/disable the on-drive defect management feature, whereby
the drive firmware tries to automatically manage defective
sectors by relocating them to "spare" sectors reserved by the
factory for such. Control of this feature via the -D option
is not supported for most modern drives since ATA-4; thus this
command may fail.
-E Set cd/dvd drive speed. This is NOT necessary for regular
operation, as the drive will automatically switch speeds on
its own. But if you want to play with it, just supply a speed
number after the option, usually a number like 2 or 4. This
can be useful in some cases, though, to smooth out DVD video
playback.
-f Sync and flush the buffer cache for the device on exit. This
operation is also performed internally as part of the -t and
-T timings and other options.
--fallocate
This option currently works only on ext4 and xfs filesystem
types. When used, this must be the only option given. It
requires two parameters: the desired file size in kilo-bytes
(byte count divided by 1024), followed by the pathname for the
new file. It will create a new file of the specified size,
but without actually having to write any data to the file.
This will normally complete very quickly, and without
thrashing the storage device.
E.g. Create a 10KByte file: hdparm --fallocate 10 temp_file
--fibmap
When used, this must be the only option given. It requires a
file path as a parameter, and will print out a list of the
block extents (sector ranges) occupied by that file on disk.
Sector numbers are given as absolute LBA numbers, referenced
from sector 0 of the physical device rather than from the
partition or filesystem. This information can then be used
for a variety of purposes, such as examining the degree of
fragmenation of larger files, or determining appropriate
sectors to deliberately corrupt during fault-injection testing
procedures.
This option uses the new FIEMAP (file extent map) ioctl() when
available, and falls back to the older FIBMAP (file block map)
ioctl() otherwise. Note that FIBMAP suffers from a 32-bit
block-number interface, and thus not work beyond 8TB or 16TB.
FIBMAP is also very slow, and does not deal well with
preallocated uncommitted extents in ext4/xfs filesystems,
unless a sync() is done before using this option.
--fwdownload
When used, this should be the only option given. It requires
a file path immediately after the option, indicating where the
new drive firmware should be read from. The contents of this
file will be sent to the drive using the (S)ATA DOWNLOAD
MICROCODE command, using either transfer protocol 7 (entire
file at once), or, if the drive supports it, transfer protocol
3 (segmented download). This command is EXTREMELY DANGEROUS
and could destroy both the drive and all data on it. DO NOT
USE THIS COMMAND. The --fwdownload-mode3 , --fwdownload-
mode3-max , and --fwdownload-mode7 variations on basic
--fwdownload allow overriding automatic protocol detection in
favour of forcing hdparm to use a specific transfer protocol,
for testing purposes only.
-F Flush the on-drive write cache buffer (older drives may not
implement this).
-g Display the drive geometry (cylinders, heads, sectors), the
size (in sectors) of the device, and the starting offset (in
sectors) of the device from the beginning of the drive.
-h Display terse usage information (help).
-H Read the temperature from some (mostly Hitachi) drives. Also
reports if the temperature is within operating condition range
(this may not be reliable). Does not cause the drive to spin
up if idle.
-i Display the identification info which the kernel drivers (IDE,
libata) have stored from boot/configuration time. This may
differ from the current information obtainable directly from
the drive itself with the -I option. The data returned may or
may not be current, depending on activity since booting the
system. For a more detailed interpretation of the
identification info, refer to AT Attachment Interface for Disk
Drives, ANSI ASC X3T9.2 working draft, revision 4a, April
19/93, and later editions.
--idle-immediate
Issue an ATA IDLE_IMMEDIATE command, to put the drive into a
lower power state. Usually the device remains spun-up.
--idle-unload
Issue an ATA IDLE_IMMEDIATE_WITH_UNLOAD command, to unload or
park the heads and put the drive into a lower power state.
Usually the device remains spun-up.
-I Request identification info directly from the drive, which is
displayed in a new expanded format with considerably more
detail than with the older -i option.
--Istdin
This is a special variation on the -I option, which accepts a
drive identification block as standard input instead of using
a /dev/hd* parameter. The format of this block must be
exactly the same as that found in the /proc/ide/*/hd*/identify
"files", or that produced by the --Istdout option described
below. This variation is designed for use with collected
"libraries" of drive identification information, and can also
be used on ATAPI drives which may give media errors with the
standard mechanism. When --Istdin is used, it must be the
*only* parameter given.
--Istdout
This option dumps the drive's identify data in hex to stdout,
in a format similar to that from /proc/ide/*/identify, and
suitable for later use with the --Istdin option.
-J Get/set the Western Digital (WD) Green Drive's "idle3" timeout
value. This timeout controls how often the drive parks its
heads and enters a low power consumption state. The factory
default is eight (8) seconds, which is a very poor choice for
use with Linux. Leaving it at the default will result in
hundreds of thousands of head load/unload cycles in a very
short period of time. The drive mechanism is only rated for
300,000 to 1,000,000 cycles, so leaving it at the default
could result in premature failure, not to mention the
performance impact of the drive often having to wake-up before
doing routine I/O.
WD supply a WDIDLE3.EXE DOS utility for tweaking this setting,
and you should use that program instead of hdparm if at all
possible. The reverse-engineered implementation in hdparm is
not as complete as the original official program, even though
it does seem to work on at a least a few drives. A full power
cycle is required for any change in setting to take effect,
regardless of which program is used to tweak things.
A setting of 30 seconds is recommended for Linux use.
Permitted values are from 8 to 12 seconds, and from 30 to 300
seconds in 30-second increments. Specify a value of zero (0)
to disable the WD idle3 timer completely (NOT RECOMMENDED!).
-k Get/set the "keep_settings_over_reset" flag for the drive.
When this flag is set, the drive will preserve the -dmu
settings over a soft reset, (as done during the error recovery
sequence). This option defaults to off, to prevent drive
reset loops which could be caused by combinations of -dmu
settings. The -k option should therefore only be set after
one has achieved confidence in correct system operation with a
chosen set of configuration settings. In practice, all that
is typically necessary to test a configuration (prior to using
-k) is to verify that the drive can be read/written, and that
no error logs (kernel messages) are generated in the process
(look in /var/log/messages on most systems).
-K Set the drive´s "keep_features_over_reset" flag. Setting this
enables the drive to retain the settings for -APSWXZ over a
soft reset (as done during the error recovery sequence). Not
all drives support this feature.
-L Set the drive´s doorlock flag. Setting this to 1 will lock
the door mechanism of some removable hard drives (e.g.
Syquest, ZIP, Jazz..), and setting it to 0 will unlock the
door mechanism. Normally, Linux maintains the door locking
mechanism automatically, depending on drive usage (locked
whenever a filesystem is mounted). But on system shutdown,
this can be a nuisance if the root partition is on a removable
disk, since the root partition is left mounted (read-only)
after shutdown. So, by using this command to unlock the door
after the root filesystem is remounted read-only, one can then
remove the cartridge from the drive after shutdown.
-m Get/set sector count for multiple sector I/O on the drive. A
setting of 0 disables this feature. Multiple sector mode (aka
IDE Block Mode), is a feature of most modern IDE hard drives,
permitting the transfer of multiple sectors per I/O interrupt,
rather than the usual one sector per interrupt. When this
feature is enabled, it typically reduces operating system
overhead for disk I/O by 30-50%. On many systems, it also
provides increased data throughput of anywhere from 5% to 50%.
Some drives, however (most notably the WD Caviar series), seem
to run slower with multiple mode enabled. Your mileage may
vary. Most drives support the minimum settings of 2, 4, 8, or
16 (sectors). Larger settings may also be possible, depending
on the drive. A setting of 16 or 32 seems optimal on many
systems. Western Digital recommends lower settings of 4 to 8
on many of their drives, due tiny (32kB) drive buffers and
non-optimized buffering algorithms. The -i option can be used
to find the maximum setting supported by an installed drive
(look for MaxMultSect in the output). Some drives claim to
support multiple mode, but lose data at some settings. Under
rare circumstances, such failures can result in massive
filesystem corruption.
--make-bad-sector
Deliberately create a bad sector (aka. "media error") on the
disk. EXCEPTIONALLY DANGEROUS. DO NOT USE THIS OPTION!! This
can be useful for testing of device/RAID error recovery
mechanisms. The sector number is given as a (base10)
parameter after the option. Depending on the device, hdparm
will choose one of two possible ATA commands for corrupting
the sector. The WRITE_LONG works on most drives, but only up
to the 28-bit sector boundary. Some very recent drives (2008)
may support the new WRITE_UNCORRECTABLE_EXT command, which
works for any LBA48 sector. If available, hdparm will use
that in preference to WRITE_LONG. The WRITE_UNCORRECTABLE_EXT
command itself presents a choice of how the new bad sector
should behave. By default, it will look like any other bad
sector, and the drive may take some time to retry and fail on
subsequent READs of the sector. However, if a single letter f
is prepended immediately in front of the first digit of the
sector number parameter, then hdparm will issue a "flagged"
WRITE_UNCORRECTABLE_EXT, which causes the drive to merely flag
the sector as bad (rather than genuinely corrupt it), and
subsequent READs of the sector will fail immediately (rather
than after several retries). Note also that the --repair-
sector option can be used to restore (any) bad sectors when
they are no longer needed, including sectors that were
genuinely bad (the drive will likely remap those to a fresh
area on the media).
-M Get/set Automatic Acoustic Management (AAM) setting. Most
modern harddisk drives have the ability to speed down the head
movements to reduce their noise output. The possible values
are between 0 and 254. 128 is the most quiet (and therefore
slowest) setting and 254 the fastest (and loudest). Some
drives have only two levels (quiet / fast), while others may
have different levels between 128 and 254. At the moment,
most drives only support 3 options, off, quiet, and fast.
These have been assigned the values 0, 128, and 254 at
present, respectively, but integer space has been incorporated
for future expansion, should this change.
-n Get or set the "ignore_write_errors" flag in the driver. Do
NOT play with this without grokking the driver source code
first.
-N Get/set max visible number of sectors, also known as the Host
Protected Area setting. Without a parameter, -N displays the
current setting, which is reported as two values: the first
gives the current max sectors setting, and the second shows
the native (real) hardware limit for the disk. The difference
between these two values indicates how many sectors of the
disk are currently hidden from the operating system, in the
form of a Host Protected Area (HPA). This area is often used
by computer makers to hold diagnostic software, and/or a copy
of the originally provided operating system for recovery
purposes. Another possible use is to hide the true capacity
of a very large disk from a BIOS/system that cannot normally
cope with drives of that size (eg. most current {2010} BIOSs
cannot deal with drives larger than 2TB, so an HPA could be
used to cause a 3TB drive to report itself as a 2TB drive).
To change the current max (VERY DANGEROUS, DATA LOSS IS
EXTREMELY LIKELY), a new value should be provided (in base10)
immediately following the -N option. This value is specified
as a count of sectors, rather than the "max sector address" of
the drive. Drives have the concept of a temporary (volatile)
setting which is lost on the next hardware reset, as well as a
more permanent (non-volatile) value which survives resets and
power cycles. By default, -N affects only the temporary
(volatile) setting. To change the permanent (non-volatile)
value, prepend a leading p character immediately before the
first digit of the value. Drives are supposed to allow only a
single permanent change per session. A hardware reset (or
power cycle) is required before another permanent -N operation
can succeed. Note that any attempt to set this value may fail
if the disk is being accessed by other software at the same
time. This is because setting the value requires a pair of
back-to-back drive commands, but there is no way to prevent
some other command from being inserted between them by the
kernel. So if it fails initially, just try again. Kernel
support for -N is buggy for many adapter types across many
kernel versions, in that an incorrect (too small) max size
value is sometimes reported. As of the 2.6.27 kernel, this
does finally seem to be working on most hardware.
--offset
Offsets to given number of GiB (1024*1024*1024) when
performing -t timings of device reads. Speed changes (about
twice) along many mechanical drives. Usually the maximum is
at the beginning, but not always. Solid-state drives (SSDs)
should show similar timings regardless of offset.
-p Attempt to reprogram the IDE interface chipset for the
specified PIO mode, or attempt to auto-tune for the "best" PIO
mode supported by the drive. This feature is supported in the
kernel for only a few "known" chipsets, and even then the
support is iffy at best. Some IDE chipsets are unable to
alter the PIO mode for a single drive, in which case this
option may cause the PIO mode for both drives to be set. Many
IDE chipsets support either fewer or more than the standard
six (0 to 5) PIO modes, so the exact speed setting that is
actually implemented will vary by chipset/driver
sophistication. Use with extreme caution! This feature
includes zero protection for the unwary, and an unsuccessful
outcome may result in severe filesystem corruption!
-P Set the maximum sector count for the drive´s internal prefetch
mechanism. Not all drives support this feature, and it was
dropped from the official spec as of ATA-4.
--prefer-ata12
When using the SAT (SCSI ATA Translation) protocol, hdparm
normally prefers to use the 16-byte command format whenever
possible. But some USB drive enclosures don't work correctly
with 16-byte commands. This option can be used to force use
of the smaller 12-byte command format with such drives.
hdparm will still revert to 16-byte commands for things that
cannot be done with the 12-byte format (e.g. sector accesses
beyond 28-bits).
-q Handle the next option quietly, suppressing normal output (but
not error messages). This is useful for reducing screen
clutter when running from system startup scripts. Not
applicable to the -i or -v or -t or -T options.
-Q Get or set the device's command queue_depth, if supported by
the hardware. This only works with 2.6.xx (or later) kernels,
and only with device and driver combinations which support
changing the queue_depth. For SATA disks, this is the Native
Command Queuing (NCQ) queue depth.
-r Get/set read-only flag for the device. When set, Linux
disallows write operations on the device.
-R Get/set Write-Read-Verify feature, if the drive supports it.
Usage: -R0 (disable) or -R1 (enable). This feature is
intended to have the drive firmware automatically read-back
any data that is written by software, to verify that the data
was successfully written. This is generally overkill, and can
slow down disk writes by as much as a factor of two (or more).
--read-sector
Reads from the specified sector number, and dumps the contents
in hex to standard output. The sector number must be given
(base10) after this option. hdparm will issue a low-level
read (completely bypassing the usual block layer read/write
mechanisms) for the specified sector. This can be used to
definitively check whether a given sector is bad (media error)
or not (doing so through the usual mechanisms can sometimes
give false positives).
--repair-sector
This is an alias for the --write-sector option. VERY
DANGEROUS.
-s Enable/disable the power-on in standby feature, if supported
by the drive. VERY DANGEROUS. Do not use unless you are
absolutely certain that both the system BIOS (or firmware) and
the operating system kernel (Linux >= 2.6.22) support probing
for drives that use this feature. When enabled, the drive is
powered-up in the standby mode to allow the controller to
sequence the spin-up of devices, reducing the instantaneous
current draw burden when many drives share a power supply.
Primarily for use in large RAID setups. This feature is
usually disabled and the drive is powered-up in the active
mode (see -C above). Note that a drive may also allow
enabling this feature by a jumper. Some SATA drives support
the control of this feature by pin 11 of the SATA power
connector. In these cases, this command may be unsupported or
may have no effect.
-S Put the drive into idle (low-power) mode, and also set the
standby (spindown) timeout for the drive. This timeout value
is used by the drive to determine how long to wait (with no
disk activity) before turning off the spindle motor to save
power. Under such circumstances, the drive may take as long
as 30 seconds to respond to a subsequent disk access, though
most drives are much quicker. The encoding of the timeout
value is somewhat peculiar. A value of zero means "timeouts
are disabled": the device will not automatically enter standby
mode. Values from 1 to 240 specify multiples of 5 seconds,
yielding timeouts from 5 seconds to 20 minutes. Values from
241 to 251 specify from 1 to 11 units of 30 minutes, yielding
timeouts from 30 minutes to 5.5 hours. A value of 252
signifies a timeout of 21 minutes. A value of 253 sets a
vendor-defined timeout period between 8 and 12 hours, and the
value 254 is reserved. 255 is interpreted as 21 minutes plus
15 seconds. Note that some older drives may have very
different interpretations of these values.
-t Perform timings of device reads for benchmark and comparison
purposes. For meaningful results, this operation should be
repeated 2-3 times on an otherwise inactive system (no other
active processes) with at least a couple of megabytes of free
memory. This displays the speed of reading through the buffer
cache to the disk without any prior caching of data. This
measurement is an indication of how fast the drive can sustain
sequential data reads under Linux, without any filesystem
overhead. To ensure accurate measurements, the buffer cache
is flushed during the processing of -t using the BLKFLSBUF
ioctl.
-T Perform timings of cache reads for benchmark and comparison
purposes. For meaningful results, this operation should be
repeated 2-3 times on an otherwise inactive system (no other
active processes) with at least a couple of megabytes of free
memory. This displays the speed of reading directly from the
Linux buffer cache without disk access. This measurement is
essentially an indication of the throughput of the processor,
cache, and memory of the system under test.
--trim-sector-ranges
For Solid State Drives (SSDs). EXCEPTIONALLY DANGEROUS. DO
NOT USE THIS OPTION!! Tells the drive firmware to discard
unneeded data sectors, destroying any data that may have been
present within them. This makes those sectors available for
immediate use by the firmware's garbage collection mechanism,
to improve scheduling for wear-leveling of the flash media.
This option expects one or more sector range pairs immediately
after the option: an LBA starting address, a colon, and a
sector count (max 65535), with no intervening spaces.
EXCEPTIONALLY DANGEROUS. DO NOT USE THIS OPTION!!
E.g. hdparm --trim-sector-ranges 1000:4 7894:16 /dev/sdz
--trim-sector-ranges-stdin
Identical to --trim-sector-ranges above, except the list of
lba:count pairs is read from stdin rather than being specified
on the command line. This can be used to avoid problems with
excessively long command lines. It also permits batching of
many more sector ranges into single commands to the drive, up
to the currently configured transfer limit (max_sectors_kb).
-u Get/set the interrupt-unmask flag for the drive. A setting of
1 permits the driver to unmask other interrupts during
processing of a disk interrupt, which greatly improves Linux´s
responsiveness and eliminates "serial port overrun" errors.
Use this feature with caution: some drive/controller
combinations do not tolerate the increased I/O latencies
possible when this feature is enabled, resulting in massive
filesystem corruption. In particular, CMD-640B and RZ1000
(E)IDE interfaces can be unreliable (due to a hardware flaw)
when this option is used with kernel versions earlier than
2.0.13. Disabling the IDE prefetch feature of these
interfaces (usually a BIOS/CMOS setting) provides a safe fix
for the problem for use with earlier kernels.
-v Display some basic settings, similar to -acdgkmur for IDE.
This is also the default behaviour when no options are
specified.
-V Display program version and exit immediately.
--verbose
Display extra diagnostics from some commands.
-w Perform a device reset (DANGEROUS). Do NOT use this option.
It exists for unlikely situations where a reboot might
otherwise be required to get a confused drive back into a
useable state.
--write-sector
Writes zeros to the specified sector number. VERY DANGEROUS.
The sector number must be given (base10) after this option.
hdparm will issue a low-level write (completely bypassing the
usual block layer read/write mechanisms) to the specified
sector. This can be used to force a drive to repair a bad
sector (media error).
-W Get/set the IDE/SATA drive´s write-caching feature.
-X Set the IDE transfer mode for (E)IDE/ATA drives. This is
typically used in combination with -d1 when enabling DMA
to/from a drive on a supported interface chipset, where -X
mdma2 is used to select multiword DMA mode2 transfers and -X
sdma1 is used to select simple mode 1 DMA transfers. With
systems which support UltraDMA burst timings, -X udma2 is used
to select UltraDMA mode2 transfers (you´ll need to prepare the
chipset for UltraDMA beforehand). Apart from that, use of
this option is seldom necessary since most/all modern IDE
drives default to their fastest PIO transfer mode at power-on.
Fiddling with this can be both needless and risky. On drives
which support alternate transfer modes, -X can be used to
switch the mode of the drive only. Prior to changing the
transfer mode, the IDE interface should be jumpered or
programmed (see -p option) for the new mode setting to prevent
loss and/or corruption of data. Use this with extreme
caution! For the PIO (Programmed Input/Output) transfer modes
used by Linux, this value is simply the desired PIO mode
number plus 8. Thus, a value of 09 sets PIO mode1, 10 enables
PIO mode2, and 11 selects PIO mode3. Setting 00 restores the
drive´s "default" PIO mode, and 01 disables IORDY. For
multiword DMA, the value used is the desired DMA mode number
plus 32. for UltraDMA, the value is the desired UltraDMA mode
number plus 64.
-y Force an IDE drive to immediately enter the low power
consumption standby mode, usually causing it to spin down.
The current power mode status can be checked using the -C
option.
-Y Force an IDE drive to immediately enter the lowest power
consumption sleep mode, causing it to shut down completely. A
hard or soft reset is required before the drive can be
accessed again (the Linux IDE driver will automatically handle
issuing a reset if/when needed). The current power mode
status can be checked using the -C option.
-z Force a kernel re-read of the partition table of the specified
device(s).
-Z Disable the automatic power-saving function of certain Seagate
drives (ST3xxx models?), to prevent them from idling/spinning-
down at inconvenient times.
These switches are DANGEROUS to experiment with, and might not work
with some kernels. USE AT YOUR OWN RISK.
--security-help
Display terse usage info for all of the --security-* options.
--security-freeze
Freeze the drive´s security settings. The drive does not
accept any security commands until next power-on reset. Use
this function in combination with --security-unlock to protect
drive from any attempt to set a new password. Can be used
standalone, too. No other options are permitted on the
command line with this one.
--security-prompt-for-password
Prompt for the --security PWD rather than getting from the
command line args. This avoids having passwords show up in
shell history or in /proc/self/cmdline during execution.
--security-unlock PWD
Unlock the drive, using password PWD. Password is given as an
ASCII string and is padded with NULs to reach 32 bytes. The
applicable drive password is selected with the --user-master
switch (default is "user" password). No other options are
permitted on the command line with this one.
--security-set-pass PWD
Lock the drive, using password PWD (Set Password) (DANGEROUS).
Password is given as an ASCII string and is padded with NULs
to reach 32 bytes. Use the special password NULL to set an
empty password. The applicable drive password is selected
with the --user-master switch (default is "user" password) and
the applicable security mode with the --security-mode switch.
No other options are permitted on the command line with this
one.
--security-disable PWD
Disable drive locking, using password PWD. Password is given
as an ASCII string and is padded with NULs to reach 32 bytes.
The applicable drive password is selected with the --user-
master switch (default is "user" password). No other options
are permitted on the command line with this one.
--security-erase PWD
Erase (locked) drive, using password PWD (DANGEROUS).
Password is given as an ASCII string and is padded with NULs
to reach 32 bytes. Use the special password NULL to represent
an empty password. The applicable drive password is selected
with the --user-master switch (default is "user" password).
No other options are permitted on the command line with this
one.
--security-erase-enhanced PWD
Enhanced erase (locked) drive, using password PWD (DANGEROUS).
Password is given as an ASCII string and is padded with NULs
to reach 32 bytes. The applicable drive password is selected
with the --user-master switch (default is "user" password).
No other options are permitted on the command line with this
one.
--user-master USER
Specifies which password (user/master) to select. Defaults to
user password. Only useful in combination with --security-
unlock, --security-set-pass, --security-disable, --security-
erase or --security-erase-enhanced.
u user password
m master password
--security-mode MODE
Specifies which security mode (high/maximum) to set. Defaults
to high. Only useful in combination with --security-set-pass.
h high security
m maximum security
THIS FEATURE IS EXPERIMENTAL AND NOT WELL TESTED. USE AT YOUR
OWN RISK.
/etc/hdparm.conf
As noted above, the -m sectcount and -u 1 options should be used with
caution at first, preferably on a read-only filesystem. Most drives
work well with these features, but a few drive/controller
combinations are not 100% compatible. Filesystem corruption may
result. Backup everything before experimenting!
Some options (e.g. -r for SCSI) may not work with old kernels as
necessary ioctl()´s were not supported.
Although this utility is intended primarily for use with SATA/IDE
hard disk devices, several of the options are also valid (and
permitted) for use with SCSI hard disk devices and MFM/RLL hard disks
with XT interfaces.
The Linux kernel up until 2.6.12 (and probably later) doesn´t handle
the security unlock and disable commands gracefully and will segfault
and in some cases even panic. The security commands however might
indeed have been executed by the drive. This poor kernel behaviour
makes the PIO data security commands rather useless at the moment.
Note that the "security erase" and "security disable" commands have
been implemented as two consecutive PIO data commands and will not
succeed on a locked drive because the second command will not be
issued after the segfault. See the code for hints how patch it to
work around this problem. Despite the segfault it is often still
possible to run two instances of hdparm consecutively and issue the
two necessary commands that way.
hdparm has been written by Mark Lord <mlord@pobox.com>, the original
primary developer and maintainer of the (E)IDE driver for Linux, and
current contributor to the libata subsystem, along with suggestions
and patches from many netfolk.
The disable Seagate auto-powersaving code is courtesy of Tomi
Leppikangas(tomilepp@paju.oulu.fi).
Security freeze command by Benjamin Benz, 2005.
PIO data out security commands by Leonard den Ottolander, 2005. Some
other parts by Benjamin Benz and others.
http://www.t13.org/ Technical Committee T13 AT Attachment (ATA/ATAPI)
Interface.
http://www.serialata.org/ Serial ATA International Organization.
http://www.compactflash.org/ CompactFlash Association.
This page is part of the hdparm (get/set ATA/SATA drive parameters
under Linux) project. Information about the project can be found at
⟨http://hdparm.sourceforge.net/⟩. It is not known how to report bugs
for this man page; if you know, please send a mail to
man-pages@man7.org. This page was obtained from the tarball
hdparm-9.53.tar.gz fetched from
⟨http://sourceforge.net/projects/hdparm/files/latest/download?source=dlp⟩
on 2018-02-02. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-to-
date source for the page, or you have corrections or improvements to
the information in this COLOPHON (which is not part of the original
manual page), send a mail to man-pages@man7.org
Version 9.51 January 2017 HDPARM(8)
Pages that refer to this page: fsync(2), proc(5)
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HTML rendering created 2018-02-02 by Michael Kerrisk, author of The Linux Programming Interface, maintainer of the Linux man-pages project. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH.
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